Phase noise in a synchronized concurrent dual-frequency oscillator

The phase noise in synchronized concurrent dual-frequency oscillators is analyzed. Two cases are considered -synchronization to external injection sources and synchronization in array of coupled identical oscillators. For small injection strengths, the phase noise behavior of synchronized concurrent dual-frequency oscillators at either of the frequencies is similar to that of synchronized single frequency oscillators. The phase noise of an injection locked concurrent dual-frequency oscillator for either of the frequencies follows the phase noise of external injection near that frequency for offsets within the locking bandwidth of the injection. For offsets outside of the locking bandwidth, the injection locked oscillator's phase noise is equal to that of free running case. In the system of two coupled concurrent dual-frequency oscillators with bilateral coupling, the phase noise at either frequency is 3dB smaller than that at the free running case for offsets smaller than the locking bandwidth. Measurement results show a good match with the theory.